GStreamer: reference counting cleanups

Simplify reference counting by using handle types

Pick-to: 6.5 6.7
Change-Id: I78788cb73e9597dc9fcd37d86d4ae179dea7bdbf
Reviewed-by: Artem Dyomin <artem.dyomin@qt.io>

12 files changed, 83 insertions, 60 deletions

diff --git a/src/plugins/multimedia/gstreamer/common/qgst.cpp b/src/plugins/multimedia/gstreamer/common/qgst.cpp
index 83d95a9e2..ebcc278d7 100644
--- a/src/plugins/multimedia/gstreamer/common/qgst.cpp
+++ b/src/plugins/multimedia/gstreamer/common/qgst.cpp
@@ -482,6 +482,14 @@ QGstCaps QGstCaps::fromCameraFormat(const QCameraFormat &format)
     return caps;
 }
 
+QGstCaps QGstCaps::copy() const
+{
+    return QGstCaps{
+        gst_caps_copy(caps()),
+        QGstCaps::HasRef,
+    };
+}
+
 QGstCaps::MemoryFormat QGstCaps::memoryFormat() const
 {
     auto *features = gst_caps_get_features(get(), 0);
diff --git a/src/plugins/multimedia/gstreamer/common/qgst_handle_types_p.h b/src/plugins/multimedia/gstreamer/common/qgst_handle_types_p.h
index b72e92db1..c37ac5971 100644
--- a/src/plugins/multimedia/gstreamer/common/qgst_handle_types_p.h
+++ b/src/plugins/multimedia/gstreamer/common/qgst_handle_types_p.h
@@ -46,7 +46,7 @@ struct QSharedHandle : private QUniqueHandle<HandleTraits>
     }
 
     QSharedHandle(const QSharedHandle &o)
-        : QSharedHandle{
+        : BaseClass{
               HandleTraits::ref(o.get()),
           }
     {
@@ -238,6 +238,7 @@ using QUniqueGstStructureHandle = QUniqueHandle<QGstImpl::QUniqueGstStructureHan
 using QUniqueGStringHandle = QUniqueHandle<QGstImpl::QUniqueGStringHandleTraits>;
 using QUniqueGErrorHandle = QUniqueHandle<QGstImpl::QUniqueGErrorHandleTraits>;
 using QFileDescriptorHandle = QUniqueHandle<QGstImpl::QFileDescriptorHandleTraits>;
+using QGstBufferHandle = QGstImpl::QGstMiniObjectHandleHelper<GstBuffer>::SharedHandle;
 using QGstContextHandle = QGstImpl::QGstMiniObjectHandleHelper<GstContext>::UniqueHandle;
 using QGstGstDateTimeHandle = QGstImpl::QGstMiniObjectHandleHelper<GstDateTime>::SharedHandle;
 using QGstPluginFeatureHandle = QGstImpl::QGstHandleHelper<GstPluginFeature>::SharedHandle;
diff --git a/src/plugins/multimedia/gstreamer/common/qgst_p.h b/src/plugins/multimedia/gstreamer/common/qgst_p.h
index ab264f552..d569a743d 100644
--- a/src/plugins/multimedia/gstreamer/common/qgst_p.h
+++ b/src/plugins/multimedia/gstreamer/common/qgst_p.h
@@ -333,6 +333,8 @@ public:
     static QGstCaps create();
 
     static QGstCaps fromCameraFormat(const QCameraFormat &format);
+
+    QGstCaps copy() const;
 };
 
 template <>
diff --git a/src/plugins/multimedia/gstreamer/common/qgstreamerbufferprobe.cpp b/src/plugins/multimedia/gstreamer/common/qgstreamerbufferprobe.cpp
index 341cb69b3..9cba810db 100644
--- a/src/plugins/multimedia/gstreamer/common/qgstreamerbufferprobe.cpp
+++ b/src/plugins/multimedia/gstreamer/common/qgstreamerbufferprobe.cpp
@@ -3,6 +3,8 @@
 
 #include <common/qgstreamerbufferprobe_p.h>
 
+#include <common/qgst_p.h>
+
 QT_BEGIN_NAMESPACE
 
 QGstreamerBufferProbe::QGstreamerBufferProbe(Flags flags)
@@ -14,10 +16,14 @@ QGstreamerBufferProbe::~QGstreamerBufferProbe() = default;
 
 void QGstreamerBufferProbe::addProbeToPad(GstPad *pad, bool downstream)
 {
-    if (GstCaps *caps = gst_pad_get_current_caps(pad)) {
-        probeCaps(caps);
-        gst_caps_unref(caps);
-    }
+    QGstCaps caps{
+        gst_pad_get_current_caps(pad),
+        QGstCaps::HasRef,
+    };
+
+    if (caps)
+        probeCaps(caps.caps());
+
     if (m_flags & ProbeCaps) {
         m_capsProbeId = gst_pad_add_probe(
                     pad,
diff --git a/src/plugins/multimedia/gstreamer/common/qgstutils.cpp b/src/plugins/multimedia/gstreamer/common/qgstutils.cpp
index d3d5f6124..40fb4b6f7 100644
--- a/src/plugins/multimedia/gstreamer/common/qgstutils.cpp
+++ b/src/plugins/multimedia/gstreamer/common/qgstutils.cpp
@@ -115,7 +115,7 @@ QList<QAudioFormat::SampleFormat> QGValue::getSampleFormats() const
     return formats;
 }
 
-void QGstUtils::setFrameTimeStamps(QVideoFrame *frame, GstBuffer *buffer)
+void QGstUtils::setFrameTimeStampsFromBuffer(QVideoFrame *frame, GstBuffer *buffer)
 {
     using namespace std::chrono;
     using namespace std::chrono_literals;
diff --git a/src/plugins/multimedia/gstreamer/common/qgstutils_p.h b/src/plugins/multimedia/gstreamer/common/qgstutils_p.h
index 4141ae0bf..c65fcf090 100644
--- a/src/plugins/multimedia/gstreamer/common/qgstutils_p.h
+++ b/src/plugins/multimedia/gstreamer/common/qgstutils_p.h
@@ -31,7 +31,7 @@ QAudioFormat audioFormatForSample(GstSample *sample);
 QAudioFormat audioFormatForCaps(const QGstCaps &caps);
 QGstCaps capsForAudioFormat(const QAudioFormat &format);
 
-void setFrameTimeStamps(QVideoFrame *frame, GstBuffer *buffer);
+void setFrameTimeStampsFromBuffer(QVideoFrame *frame, GstBuffer *buffer);
 } // namespace QGstUtils
 
 GList *qt_gst_video_sinks();
diff --git a/src/plugins/multimedia/gstreamer/common/qgstvideobuffer.cpp b/src/plugins/multimedia/gstreamer/common/qgstvideobuffer.cpp
index 101d56af6..6552786bb 100644
--- a/src/plugins/multimedia/gstreamer/common/qgstvideobuffer.cpp
+++ b/src/plugins/multimedia/gstreamer/common/qgstvideobuffer.cpp
@@ -51,18 +51,19 @@ QT_BEGIN_NAMESPACE
 #define DRM_FORMAT_GR1616       fourcc_code('G', 'R', '3', '2') /* [31:0] G:R 16:16 little endian */
 #define DRM_FORMAT_BGRA1010102  fourcc_code('B', 'A', '3', '0') /* [31:0] B:G:R:A 10:10:10:2 little endian */
 
-QGstVideoBuffer::QGstVideoBuffer(GstBuffer *buffer, const GstVideoInfo &info, QGstreamerVideoSink *sink,
-                                 const QVideoFrameFormat &frameFormat,
+QGstVideoBuffer::QGstVideoBuffer(QGstBufferHandle buffer, const GstVideoInfo &info,
+                                 QGstreamerVideoSink *sink, const QVideoFrameFormat &frameFormat,
                                  QGstCaps::MemoryFormat format)
-    : QAbstractVideoBuffer((sink && sink->rhi() && format != QGstCaps::CpuMemory) ?
-                            QVideoFrame::RhiTextureHandle : QVideoFrame::NoHandle, sink ? sink->rhi() : nullptr)
-    , memoryFormat(format)
-    , m_frameFormat(frameFormat)
-    , m_rhi(sink ? sink->rhi() : nullptr)
-    , m_videoInfo(info)
-    , m_buffer(buffer)
+    : QAbstractVideoBuffer((sink && sink->rhi() && format != QGstCaps::CpuMemory)
+                                   ? QVideoFrame::RhiTextureHandle
+                                   : QVideoFrame::NoHandle,
+                           sink ? sink->rhi() : nullptr),
+      memoryFormat(format),
+      m_frameFormat(frameFormat),
+      m_rhi(sink ? sink->rhi() : nullptr),
+      m_videoInfo(info),
+      m_buffer(std::move(buffer))
 {
-    gst_buffer_ref(m_buffer);
     if (sink) {
         eglDisplay =  sink->eglDisplay();
         eglImageTargetTexture2D = sink->eglImageTargetTexture2D();
@@ -76,8 +77,6 @@ QGstVideoBuffer::QGstVideoBuffer(GstBuffer *buffer, const GstVideoInfo &info, QG
 QGstVideoBuffer::~QGstVideoBuffer()
 {
     unmap();
-
-    gst_buffer_unref(m_buffer);
 }
 
 
@@ -96,7 +95,7 @@ QAbstractVideoBuffer::MapData QGstVideoBuffer::map(QVideoFrame::MapMode mode)
         return mapData;
 
     if (m_videoInfo.finfo->n_planes == 0) {         // Encoded
-        if (gst_buffer_map(m_buffer, &m_frame.map[0], flags)) {
+        if (gst_buffer_map(m_buffer.get(), &m_frame.map[0], flags)) {
             mapData.nPlanes = 1;
             mapData.bytesPerLine[0] = -1;
             mapData.size[0] = m_frame.map[0].size;
@@ -104,7 +103,7 @@ QAbstractVideoBuffer::MapData QGstVideoBuffer::map(QVideoFrame::MapMode mode)
 
             m_mode = mode;
         }
-    } else if (gst_video_frame_map(&m_frame, &m_videoInfo, m_buffer, flags)) {
+    } else if (gst_video_frame_map(&m_frame, &m_videoInfo, m_buffer.get(), flags)) {
         mapData.nPlanes = GST_VIDEO_FRAME_N_PLANES(&m_frame);
 
         for (guint i = 0; i < GST_VIDEO_FRAME_N_PLANES(&m_frame); ++i) {
@@ -122,7 +121,7 @@ void QGstVideoBuffer::unmap()
 {
     if (m_mode != QVideoFrame::NotMapped) {
         if (m_videoInfo.finfo->n_planes == 0)
-            gst_buffer_unmap(m_buffer, &m_frame.map[0]);
+            gst_buffer_unmap(m_buffer.get(), &m_frame.map[0]);
         else
             gst_video_frame_unmap(&m_frame);
     }
@@ -258,9 +257,10 @@ private:
     std::unique_ptr<QRhiTexture> m_textures[QVideoTextureHelper::TextureDescription::maxPlanes];
 };
 
-
-static GlTextures mapFromGlTexture(GstBuffer *buffer, GstVideoFrame &frame, GstVideoInfo &videoInfo)
+static GlTextures mapFromGlTexture(const QGstBufferHandle &bufferHandle, GstVideoFrame &frame,
+                                   GstVideoInfo &videoInfo)
 {
+    GstBuffer *buffer = bufferHandle.get();
     auto *mem = GST_GL_BASE_MEMORY_CAST(gst_buffer_peek_memory(buffer, 0));
     if (!mem)
         return {};
@@ -293,10 +293,12 @@ static GlTextures mapFromGlTexture(GstBuffer *buffer, GstVideoFrame &frame, GstV
 }
 
 #if GST_GL_HAVE_PLATFORM_EGL && QT_CONFIG(linux_dmabuf)
-static GlTextures mapFromDmaBuffer(QRhi *rhi, GstBuffer *buffer, GstVideoFrame &frame,
-                                   GstVideoInfo &videoInfo, Qt::HANDLE eglDisplay,
-                                   QFunctionPointer eglImageTargetTexture2D)
+static GlTextures mapFromDmaBuffer(QRhi *rhi, const QGstBufferHandle &bufferHandle,
+                                   GstVideoFrame &frame, GstVideoInfo &videoInfo,
+                                   Qt::HANDLE eglDisplay, QFunctionPointer eglImageTargetTexture2D)
 {
+    GstBuffer *buffer = bufferHandle.get();
+
     Q_ASSERT(gst_is_dmabuf_memory(gst_buffer_peek_memory(buffer, 0)));
     Q_ASSERT(eglDisplay);
     Q_ASSERT(eglImageTargetTexture2D);
@@ -377,14 +379,15 @@ std::unique_ptr<QVideoFrameTextures> QGstVideoBuffer::mapTextures(QRhi *rhi)
 
 #if QT_CONFIG(gstreamer_gl)
     GlTextures textures = {};
-    if (memoryFormat == QGstCaps::GLTexture) {
+    if (memoryFormat == QGstCaps::GLTexture)
         textures = mapFromGlTexture(m_buffer, m_frame, m_videoInfo);
-    }
-#if GST_GL_HAVE_PLATFORM_EGL && QT_CONFIG(linux_dmabuf)
-    else if (memoryFormat == QGstCaps::DMABuf) {
-        textures = mapFromDmaBuffer(m_rhi, m_buffer, m_frame, m_videoInfo, eglDisplay, eglImageTargetTexture2D);
-    }
-#endif
+
+#  if GST_GL_HAVE_PLATFORM_EGL && QT_CONFIG(linux_dmabuf)
+    else if (memoryFormat == QGstCaps::DMABuf)
+        textures = mapFromDmaBuffer(m_rhi, m_buffer, m_frame, m_videoInfo, eglDisplay,
+                                    eglImageTargetTexture2D);
+
+#  endif
     if (textures.count > 0)
         return std::make_unique<QGstQVideoFrameTextures>(rhi, QSize{m_videoInfo.width, m_videoInfo.height},
                                                          m_frameFormat.pixelFormat(), textures);
diff --git a/src/plugins/multimedia/gstreamer/common/qgstvideobuffer_p.h b/src/plugins/multimedia/gstreamer/common/qgstvideobuffer_p.h
index 27567c9f7..151927d3d 100644
--- a/src/plugins/multimedia/gstreamer/common/qgstvideobuffer_p.h
+++ b/src/plugins/multimedia/gstreamer/common/qgstvideobuffer_p.h
@@ -30,12 +30,10 @@ class QOpenGLContext;
 class QGstVideoBuffer final : public QAbstractVideoBuffer
 {
 public:
-
-    QGstVideoBuffer(GstBuffer *buffer, const GstVideoInfo &info, QGstreamerVideoSink *sink,
+    QGstVideoBuffer(QGstBufferHandle buffer, const GstVideoInfo &info, QGstreamerVideoSink *sink,
                     const QVideoFrameFormat &frameFormat, QGstCaps::MemoryFormat format);
     ~QGstVideoBuffer();
 
-    GstBuffer *buffer() const { return m_buffer; }
     QVideoFrame::MapMode mapMode() const override;
 
     MapData map(QVideoFrame::MapMode mode) override;
@@ -49,7 +47,7 @@ private:
     QRhi *m_rhi = nullptr;
     mutable GstVideoInfo m_videoInfo;
     mutable GstVideoFrame m_frame{};
-    GstBuffer *m_buffer = nullptr;
+    const QGstBufferHandle m_buffer;
     QVideoFrame::MapMode m_mode = QVideoFrame::NotMapped;
     Qt::HANDLE eglDisplay = nullptr;
     QFunctionPointer eglImageTargetTexture2D = nullptr;
diff --git a/src/plugins/multimedia/gstreamer/common/qgstvideorenderersink.cpp b/src/plugins/multimedia/gstreamer/common/qgstvideorenderersink.cpp
index ec4cbb468..4e9619b11 100644
--- a/src/plugins/multimedia/gstreamer/common/qgstvideorenderersink.cpp
+++ b/src/plugins/multimedia/gstreamer/common/qgstvideorenderersink.cpp
@@ -177,7 +177,7 @@ void QGstVideoRenderer::flush()
     QMutexLocker locker(&m_mutex);
 
     m_flush = true;
-    m_renderBuffer = nullptr;
+    m_renderBuffer = {};
     m_renderCondition.wakeAll();
 
     notify();
@@ -189,11 +189,14 @@ GstFlowReturn QGstVideoRenderer::render(GstBuffer *buffer)
     qCDebug(qLcGstVideoRenderer) << "QGstVideoRenderer::render";
 
     m_renderReturn = GST_FLOW_OK;
-    m_renderBuffer = buffer;
+    m_renderBuffer = QGstBufferHandle{
+        buffer,
+        QGstBufferHandle::NeedsRef,
+    };
 
     waitForAsyncEvent(&locker, &m_renderCondition, 300);
 
-    m_renderBuffer = nullptr;
+    m_renderBuffer = {};
 
     return m_renderReturn;
 }
@@ -353,19 +356,17 @@ bool QGstVideoRenderer::handleEvent(QMutexLocker<QMutex> *locker)
         }
 
     } else if (m_renderBuffer) {
-        GstBuffer *buffer = m_renderBuffer;
-        m_renderBuffer = nullptr;
+        QGstBufferHandle buffer = std::move(m_renderBuffer);
         m_renderReturn = GST_FLOW_ERROR;
 
         qCDebug(qLcGstVideoRenderer) << "QGstVideoRenderer::handleEvent(renderBuffer)" << m_active << m_sink;
         if (m_active && m_sink) {
-            gst_buffer_ref(buffer);
 
             locker->unlock();
 
             m_flushed = false;
 
-            GstVideoCropMeta *meta = gst_buffer_get_video_crop_meta(buffer);
+            GstVideoCropMeta *meta = gst_buffer_get_video_crop_meta(buffer.get());
             if (meta) {
                 QRect vp(meta->x, meta->y, meta->width, meta->height);
                 if (m_format.viewport() != vp) {
@@ -381,7 +382,7 @@ bool QGstVideoRenderer::handleEvent(QMutexLocker<QMutex> *locker)
             } else {
                 QGstVideoBuffer *videoBuffer = new QGstVideoBuffer(buffer, m_videoInfo, m_sink, m_format, memoryFormat);
                 QVideoFrame frame(videoBuffer, m_format);
-                QGstUtils::setFrameTimeStamps(&frame, buffer);
+                QGstUtils::setFrameTimeStampsFromBuffer(&frame, buffer.get());
                 frame.setMirrored(m_frameMirrored);
                 frame.setRotation(m_frameRotationAngle);
 
@@ -389,8 +390,6 @@ bool QGstVideoRenderer::handleEvent(QMutexLocker<QMutex> *locker)
                 m_sink->setVideoFrame(frame);
             }
 
-            gst_buffer_unref(buffer);
-
             locker->relock();
 
             m_renderReturn = GST_FLOW_OK;
diff --git a/src/plugins/multimedia/gstreamer/common/qgstvideorenderersink_p.h b/src/plugins/multimedia/gstreamer/common/qgstvideorenderersink_p.h
index e381e48e1..99d1b0ac8 100644
--- a/src/plugins/multimedia/gstreamer/common/qgstvideorenderersink_p.h
+++ b/src/plugins/multimedia/gstreamer/common/qgstvideorenderersink_p.h
@@ -77,7 +77,7 @@ private:
     const QGstCaps m_surfaceCaps;
 
     QGstCaps m_startCaps;
-    GstBuffer *m_renderBuffer = nullptr;
+    QGstBufferHandle m_renderBuffer;
 
     bool m_notified = false;
     bool m_stop = false;
diff --git a/src/plugins/multimedia/gstreamer/mediacapture/qgstreamerimagecapture.cpp b/src/plugins/multimedia/gstreamer/mediacapture/qgstreamerimagecapture.cpp
index cb1d174cd..6e518e9fb 100644
--- a/src/plugins/multimedia/gstreamer/mediacapture/qgstreamerimagecapture.cpp
+++ b/src/plugins/multimedia/gstreamer/mediacapture/qgstreamerimagecapture.cpp
@@ -145,15 +145,15 @@ int QGstreamerImageCapture::doCapture(const QString &fileName)
 
 void QGstreamerImageCapture::setResolution(const QSize &resolution)
 {
-    auto padCaps = QGstCaps(gst_pad_get_current_caps(bin.staticPad("sink").pad()), QGstCaps::HasRef);
+    QGstCaps padCaps = bin.staticPad("sink").currentCaps();
     if (padCaps.isNull()) {
         qDebug() << "Camera not ready";
         return;
     }
-    auto caps = QGstCaps(gst_caps_copy(padCaps.caps()), QGstCaps::HasRef);
-    if (caps.isNull()) {
+    QGstCaps caps = padCaps.copy();
+    if (caps.isNull())
         return;
-    }
+
     gst_caps_set_simple(caps.caps(), "width", G_TYPE_INT, resolution.width(), "height", G_TYPE_INT,
                         resolution.height(), nullptr);
     filter.set("caps", caps);
@@ -165,12 +165,16 @@ bool QGstreamerImageCapture::probeBuffer(GstBuffer *buffer)
         return false;
     qCDebug(qLcImageCaptureGst) << "probe buffer";
 
+    QGstBufferHandle bufferHandle{
+        buffer,
+        QGstBufferHandle::NeedsRef,
+    };
+
     passImage = false;
 
     emit readyForCaptureChanged(isReadyForCapture());
 
-    auto caps = QGstCaps(gst_pad_get_current_caps(bin.staticPad("sink").pad()), QGstCaps::HasRef);
-
+    QGstCaps caps = bin.staticPad("sink").currentCaps();
     auto memoryFormat = caps.memoryFormat();
 
     GstVideoInfo previewInfo;
@@ -180,7 +184,9 @@ bool QGstreamerImageCapture::probeBuffer(GstBuffer *buffer)
         std::tie(fmt, previewInfo) = std::move(*optionalFormatAndVideoInfo);
 
     auto *sink = m_session->gstreamerVideoSink();
-    auto *gstBuffer = new QGstVideoBuffer(buffer, previewInfo, sink, fmt, memoryFormat);
+    auto *gstBuffer = new QGstVideoBuffer{
+        std::move(bufferHandle), previewInfo, sink, fmt, memoryFormat,
+    };
     QVideoFrame frame(gstBuffer, fmt);
     QImage img = frame.toImage();
     if (img.isNull()) {
diff --git a/src/plugins/multimedia/gstreamer/mediacapture/qgstreamermediacapture.cpp b/src/plugins/multimedia/gstreamer/mediacapture/qgstreamermediacapture.cpp
index 839187a9d..0574a1f1a 100644
--- a/src/plugins/multimedia/gstreamer/mediacapture/qgstreamermediacapture.cpp
+++ b/src/plugins/multimedia/gstreamer/mediacapture/qgstreamermediacapture.cpp
@@ -198,12 +198,12 @@ void QGstreamerMediaCapture::linkEncoder(QGstPad audioSink, QGstPad videoSink)
 {
     gstPipeline.modifyPipelineWhileNotRunning([&] {
         if (!gstVideoTee.isNull() && !videoSink.isNull()) {
-            auto caps = gst_pad_get_current_caps(gstVideoTee.sink().pad());
+            QGstCaps caps = gstVideoTee.sink().currentCaps();
 
             encoderVideoCapsFilter =
                     QGstElement::createFromFactory("capsfilter", "encoderVideoCapsFilter");
             Q_ASSERT(encoderVideoCapsFilter);
-            encoderVideoCapsFilter.set("caps", QGstCaps(caps, QGstCaps::HasRef));
+            encoderVideoCapsFilter.set("caps", caps);
 
             gstPipeline.add(encoderVideoCapsFilter);
 
@@ -213,12 +213,12 @@ void QGstreamerMediaCapture::linkEncoder(QGstPad audioSink, QGstPad videoSink)
         }
 
         if (!gstAudioTee.isNull() && !audioSink.isNull()) {
-            auto caps = gst_pad_get_current_caps(gstAudioTee.sink().pad());
+            QGstCaps caps = gstAudioTee.sink().currentCaps();
 
             encoderAudioCapsFilter =
                     QGstElement::createFromFactory("capsfilter", "encoderAudioCapsFilter");
             Q_ASSERT(encoderAudioCapsFilter);
-            encoderAudioCapsFilter.set("caps", QGstCaps(caps, QGstCaps::HasRef));
+            encoderAudioCapsFilter.set("caps", caps);
 
             gstPipeline.add(encoderAudioCapsFilter);